Summary

• The Cisco CallManager, running certain software releases, has a vulnerability wherein a memory leak in the CTI Framework authentication can cause the server to crash and result in a reload. This vulnerability can be exploited to initiate a denial of service (DoS) attack.

  This vulnerability is documented as Cisco bug ID CSCdv28302. There are workarounds available to mitigate the vulnerability.

  This advisory is available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20020327-cm-ctifw-leak.

Affected Products

• This section provides details on affected products.

  Vulnerable Products

  To determine if a product is vulnerable, review the list below. If the software versions or configuration information are provided, then only those combinations are vulnerable.

  • Cisco CallManager 3.1
    

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by these vulnerabilities.

Details

• A memory leak in the Cisco CallManager has been attributed to the failure of a user to properly authenticate when using Computer Telephony Integration (CTI). This behavior is most commonly seen on CallManager systems immediately following the integration with a customer directory such as Active Directory (AD) or Netscape. The most common cause in this scenario is that the WebAttendant user, CTI Framework (CTIFW), has not been configured with a valid password in the customer directory. Please note that this problem will occur even on systems that do not utilize the WebAttendant since the Telephony Call Dispatch (TCD) service is always enabled by default. The CCMAdmin->Global Directory and "Add a New User" configuration pages stop working if CTIFW user is not configured or the CTI user's password is incorrect. Various other components such as RIS Data Collector may also fail to function properly.

  • CSCdv28302
    This vulnerability is documented as Cisco Bug ID CSCdv28302.
    

  Problem Symptoms

  There are several indicators available in determining if this problem is at the root.

  LDAP Leak Detection

  Tool	Message
  Event Viewer	Error: kCtiProviderOpenFailure - CTI application failed to open provider CTIconnectionId: 485 Login User Id: CtiFw ReasonCode: 2362179680 IPAddress: 172.21.12.44 App ID: Cisco CTIManager Cluster ID: JMTAO-CM2-Cluster Node ID: JMTAO-CM2 CTI Application ID: Cisco Telephony Call Dispatcher Process ID: 0 Process Name: CtiHandler Provider Name: CTI Framework Explanation: Application is unable to open provider. Recommended Action: Check the reason code and correct the problem. Restart CTIManager if problem persists..
  Task Manager	From the Task Manager select the Processes tab, click View and then Select Columns... Check Handle Count and click OK. Click on the Handles column to sort by handles used. You will observe that the CTIManager.exe is consuming a large number of handles (> 500).
  DOS netstat	Another diagnostic tool is to run "netstat -na" from a DOS command prompt on the CM server. A very large number of established connections to TCP port 389 if CallManager is integrated with AD or port 8404 when CallManager is integrated with DCD.

Workarounds

• Configure the ctifw user by following the instructions at: /en/US/docs/voice_ip_comm/cucm/install/3_0/ad_3011.html#xtocid30717

  Step	Action
  1	Set the password for the user in the corporate directory using your standard user management tools.
  2	On a Cisco CallManager server, choose Start > Run and enter command to open a command prompt. Click OK.
  3	Enter the command, PasswordUtils; for example, "passwordUtils my_passphrase"
  4	The previous action generates an encrypted password. Copy the password into the Windows clipboard.
  5	Choose Start > Run.
  6	Enter regedit into the Open field and then click OK.
  7	Browse to \\HKEY_LOCAL_MACHINE\Software\Cisco Systems, Inc.\Directory Configuration within the registry.
  8	Delete the value CTIFWPW and paste the encrypted password from Step 3 into the field.
  9	Restart the Cisco Telephony Call Dispatcher service by choosing Start > Programs > Administrative Tools > Services. Highlight the service in the list; right click on the service and then click Restart from the drop-down list.
  10	Repeat Step 2 through Step 9 for each Cisco CallManager server in the cluster.

  IMPORTANT: Please note that you must reboot the CM server in all cases to reset the established TCP connections and recover the lost memory.

  Alternatively, if you are not using the Cisco WebAttendant and/or the Cisco Telephony Call Dispatcher Service, set it to "manual" or "disabled" from the "Services" control panel.

Fixed Software

• When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.

  In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center ("TAC") or your contracted maintenance provider for assistance.

  Version Affected	Fixed Regular Release (available now) Fix carries forward into all later versions
  Version 3.1	Upgrade to 3.1(3a)

Exploitation and Public Announcements

• The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities described in this advisory.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20020327-cm-ctifw-leak

Revision History

• Revision 1.1	2002-Mar-28	Corrected first fixed release
  Revision 1.0	2002-Mar-27	Initial Public Release

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